In a conventional router table assembly, a router is hung beneath the assembly's working surface such that a routing tool or "bit" driven by the router extends upwardly through a hole in the assembly's working surface to engage a workpiece manipulated by an operator on the working surface. The router is either secured directly to the underside of the table or, more preferably, the router is secured to a throat plate, which is typically a thin panel which is received and supported in a complementary hole or recess formed in the assembly's working surface, with the upper surface of the panel being flush with the working surface.
Prior art throat plates often comprise a simple, rectangular plate, commonly formed of an acrylic, having a central aperture through which the routing bit may extend. Unfortunately, router table assemblies employing such nonadjustable throat plates must necessarily rely upon accurate and reliable positioning of a fence in order to achieve consistent "final cut" dimensions. Complex and costly fence-locating mechanisms are thus required in assemblies employing such nonadjustable plates particularly where "fine tuning" of fence position is periodically required.
The prior art alternatively teaches throat plates which employ a lead screw and sliding plate system to achieve limited adjustability relative to a fence. Such known adjustable throat plates, however, are complex and costly to manufacture. Moreover, such known adjustable throat plates are often difficult to adjust quickly and reliably. Accordingly, router table assemblies employing such known adjustable throat plates likewise employ the complex and costly fence-positioning mechanisms used with nonadjustable throat plates.